xref: /linux/drivers/acpi/acpica/tbfadt.c (revision 24168c5e6dfbdd5b414f048f47f75d64533296ca)
1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2 /******************************************************************************
3  *
4  * Module Name: tbfadt   - FADT table utilities
5  *
6  * Copyright (C) 2000 - 2023, Intel Corp.
7  *
8  *****************************************************************************/
9 
10 #include <acpi/acpi.h>
11 #include "accommon.h"
12 #include "actables.h"
13 
14 #define _COMPONENT          ACPI_TABLES
15 ACPI_MODULE_NAME("tbfadt")
16 
17 /* Local prototypes */
18 static void
19 acpi_tb_init_generic_address(struct acpi_generic_address *generic_address,
20 			     u8 space_id,
21 			     u8 byte_width,
22 			     u64 address, const char *register_name, u8 flags);
23 
24 static void acpi_tb_convert_fadt(void);
25 
26 static void acpi_tb_setup_fadt_registers(void);
27 
28 static u64
29 acpi_tb_select_address(char *register_name, u32 address32, u64 address64);
30 
31 /* Table for conversion of FADT to common internal format and FADT validation */
32 
33 typedef struct acpi_fadt_info {
34 	const char *name;
35 	u16 address64;
36 	u16 address32;
37 	u16 length;
38 	u8 default_length;
39 	u8 flags;
40 
41 } acpi_fadt_info;
42 
43 #define ACPI_FADT_OPTIONAL          0
44 #define ACPI_FADT_REQUIRED          1
45 #define ACPI_FADT_SEPARATE_LENGTH   2
46 #define ACPI_FADT_GPE_REGISTER      4
47 
48 static struct acpi_fadt_info fadt_info_table[] = {
49 	{"Pm1aEventBlock",
50 	 ACPI_FADT_OFFSET(xpm1a_event_block),
51 	 ACPI_FADT_OFFSET(pm1a_event_block),
52 	 ACPI_FADT_OFFSET(pm1_event_length),
53 	 ACPI_PM1_REGISTER_WIDTH * 2,	/* Enable + Status register */
54 	 ACPI_FADT_REQUIRED},
55 
56 	{"Pm1bEventBlock",
57 	 ACPI_FADT_OFFSET(xpm1b_event_block),
58 	 ACPI_FADT_OFFSET(pm1b_event_block),
59 	 ACPI_FADT_OFFSET(pm1_event_length),
60 	 ACPI_PM1_REGISTER_WIDTH * 2,	/* Enable + Status register */
61 	 ACPI_FADT_OPTIONAL},
62 
63 	{"Pm1aControlBlock",
64 	 ACPI_FADT_OFFSET(xpm1a_control_block),
65 	 ACPI_FADT_OFFSET(pm1a_control_block),
66 	 ACPI_FADT_OFFSET(pm1_control_length),
67 	 ACPI_PM1_REGISTER_WIDTH,
68 	 ACPI_FADT_REQUIRED},
69 
70 	{"Pm1bControlBlock",
71 	 ACPI_FADT_OFFSET(xpm1b_control_block),
72 	 ACPI_FADT_OFFSET(pm1b_control_block),
73 	 ACPI_FADT_OFFSET(pm1_control_length),
74 	 ACPI_PM1_REGISTER_WIDTH,
75 	 ACPI_FADT_OPTIONAL},
76 
77 	{"Pm2ControlBlock",
78 	 ACPI_FADT_OFFSET(xpm2_control_block),
79 	 ACPI_FADT_OFFSET(pm2_control_block),
80 	 ACPI_FADT_OFFSET(pm2_control_length),
81 	 ACPI_PM2_REGISTER_WIDTH,
82 	 ACPI_FADT_SEPARATE_LENGTH},
83 
84 	{"PmTimerBlock",
85 	 ACPI_FADT_OFFSET(xpm_timer_block),
86 	 ACPI_FADT_OFFSET(pm_timer_block),
87 	 ACPI_FADT_OFFSET(pm_timer_length),
88 	 ACPI_PM_TIMER_WIDTH,
89 	 ACPI_FADT_SEPARATE_LENGTH},	/* ACPI 5.0A: Timer is optional */
90 
91 	{"Gpe0Block",
92 	 ACPI_FADT_OFFSET(xgpe0_block),
93 	 ACPI_FADT_OFFSET(gpe0_block),
94 	 ACPI_FADT_OFFSET(gpe0_block_length),
95 	 0,
96 	 ACPI_FADT_SEPARATE_LENGTH | ACPI_FADT_GPE_REGISTER},
97 
98 	{"Gpe1Block",
99 	 ACPI_FADT_OFFSET(xgpe1_block),
100 	 ACPI_FADT_OFFSET(gpe1_block),
101 	 ACPI_FADT_OFFSET(gpe1_block_length),
102 	 0,
103 	 ACPI_FADT_SEPARATE_LENGTH | ACPI_FADT_GPE_REGISTER}
104 };
105 
106 #define ACPI_FADT_INFO_ENTRIES \
107 			(sizeof (fadt_info_table) / sizeof (struct acpi_fadt_info))
108 
109 /* Table used to split Event Blocks into separate status/enable registers */
110 
111 typedef struct acpi_fadt_pm_info {
112 	struct acpi_generic_address *target;
113 	u16 source;
114 	u8 register_num;
115 
116 } acpi_fadt_pm_info;
117 
118 static struct acpi_fadt_pm_info fadt_pm_info_table[] = {
119 	{&acpi_gbl_xpm1a_status,
120 	 ACPI_FADT_OFFSET(xpm1a_event_block),
121 	 0},
122 
123 	{&acpi_gbl_xpm1a_enable,
124 	 ACPI_FADT_OFFSET(xpm1a_event_block),
125 	 1},
126 
127 	{&acpi_gbl_xpm1b_status,
128 	 ACPI_FADT_OFFSET(xpm1b_event_block),
129 	 0},
130 
131 	{&acpi_gbl_xpm1b_enable,
132 	 ACPI_FADT_OFFSET(xpm1b_event_block),
133 	 1}
134 };
135 
136 #define ACPI_FADT_PM_INFO_ENTRIES \
137 			(sizeof (fadt_pm_info_table) / sizeof (struct acpi_fadt_pm_info))
138 
139 /*******************************************************************************
140  *
141  * FUNCTION:    acpi_tb_init_generic_address
142  *
143  * PARAMETERS:  generic_address     - GAS struct to be initialized
144  *              space_id            - ACPI Space ID for this register
145  *              byte_width          - Width of this register
146  *              address             - Address of the register
147  *              register_name       - ASCII name of the ACPI register
148  *
149  * RETURN:      None
150  *
151  * DESCRIPTION: Initialize a Generic Address Structure (GAS)
152  *              See the ACPI specification for a full description and
153  *              definition of this structure.
154  *
155  ******************************************************************************/
156 
157 static void
158 acpi_tb_init_generic_address(struct acpi_generic_address *generic_address,
159 			     u8 space_id,
160 			     u8 byte_width,
161 			     u64 address, const char *register_name, u8 flags)
162 {
163 	u8 bit_width;
164 
165 	/*
166 	 * Bit width field in the GAS is only one byte long, 255 max.
167 	 * Check for bit_width overflow in GAS.
168 	 */
169 	bit_width = (u8)(byte_width * 8);
170 	if (byte_width > 31) {	/* (31*8)=248, (32*8)=256 */
171 		/*
172 		 * No error for GPE blocks, because we do not use the bit_width
173 		 * for GPEs, the legacy length (byte_width) is used instead to
174 		 * allow for a large number of GPEs.
175 		 */
176 		if (!(flags & ACPI_FADT_GPE_REGISTER)) {
177 			ACPI_ERROR((AE_INFO,
178 				    "%s - 32-bit FADT register is too long (%u bytes, %u bits) "
179 				    "to convert to GAS struct - 255 bits max, truncating",
180 				    register_name, byte_width,
181 				    (byte_width * 8)));
182 		}
183 
184 		bit_width = 255;
185 	}
186 
187 	/*
188 	 * The 64-bit Address field is non-aligned in the byte packed
189 	 * GAS struct.
190 	 */
191 	ACPI_MOVE_64_TO_64(&generic_address->address, &address);
192 
193 	/* All other fields are byte-wide */
194 
195 	generic_address->space_id = space_id;
196 	generic_address->bit_width = bit_width;
197 	generic_address->bit_offset = 0;
198 	generic_address->access_width = 0;	/* Access width ANY */
199 }
200 
201 /*******************************************************************************
202  *
203  * FUNCTION:    acpi_tb_select_address
204  *
205  * PARAMETERS:  register_name       - ASCII name of the ACPI register
206  *              address32           - 32-bit address of the register
207  *              address64           - 64-bit address of the register
208  *
209  * RETURN:      The resolved 64-bit address
210  *
211  * DESCRIPTION: Select between 32-bit and 64-bit versions of addresses within
212  *              the FADT. Used for the FACS and DSDT addresses.
213  *
214  * NOTES:
215  *
216  * Check for FACS and DSDT address mismatches. An address mismatch between
217  * the 32-bit and 64-bit address fields (FIRMWARE_CTRL/X_FIRMWARE_CTRL and
218  * DSDT/X_DSDT) could be a corrupted address field or it might indicate
219  * the presence of two FACS or two DSDT tables.
220  *
221  * November 2013:
222  * By default, as per the ACPICA specification, a valid 64-bit address is
223  * used regardless of the value of the 32-bit address. However, this
224  * behavior can be overridden via the acpi_gbl_use32_bit_fadt_addresses flag.
225  *
226  ******************************************************************************/
227 
228 static u64
229 acpi_tb_select_address(char *register_name, u32 address32, u64 address64)
230 {
231 
232 	if (!address64) {
233 
234 		/* 64-bit address is zero, use 32-bit address */
235 
236 		return ((u64)address32);
237 	}
238 
239 	if (address32 && (address64 != (u64)address32)) {
240 
241 		/* Address mismatch between 32-bit and 64-bit versions */
242 
243 		ACPI_BIOS_WARNING((AE_INFO,
244 				   "32/64X %s address mismatch in FADT: "
245 				   "0x%8.8X/0x%8.8X%8.8X, using %u-bit address",
246 				   register_name, address32,
247 				   ACPI_FORMAT_UINT64(address64),
248 				   acpi_gbl_use32_bit_fadt_addresses ? 32 :
249 				   64));
250 
251 		/* 32-bit address override */
252 
253 		if (acpi_gbl_use32_bit_fadt_addresses) {
254 			return ((u64)address32);
255 		}
256 	}
257 
258 	/* Default is to use the 64-bit address */
259 
260 	return (address64);
261 }
262 
263 /*******************************************************************************
264  *
265  * FUNCTION:    acpi_tb_parse_fadt
266  *
267  * PARAMETERS:  None
268  *
269  * RETURN:      None
270  *
271  * DESCRIPTION: Initialize the FADT, DSDT and FACS tables
272  *              (FADT contains the addresses of the DSDT and FACS)
273  *
274  ******************************************************************************/
275 
276 void acpi_tb_parse_fadt(void)
277 {
278 	u32 length;
279 	struct acpi_table_header *table;
280 	struct acpi_table_desc *fadt_desc;
281 	acpi_status status;
282 
283 	/*
284 	 * The FADT has multiple versions with different lengths,
285 	 * and it contains pointers to both the DSDT and FACS tables.
286 	 *
287 	 * Get a local copy of the FADT and convert it to a common format
288 	 * Map entire FADT, assumed to be smaller than one page.
289 	 */
290 	fadt_desc = &acpi_gbl_root_table_list.tables[acpi_gbl_fadt_index];
291 	status = acpi_tb_get_table(fadt_desc, &table);
292 	if (ACPI_FAILURE(status)) {
293 		return;
294 	}
295 	length = fadt_desc->length;
296 
297 	/*
298 	 * Validate the FADT checksum before we copy the table. Ignore
299 	 * checksum error as we want to try to get the DSDT and FACS.
300 	 */
301 	(void)acpi_ut_verify_checksum(table, length);
302 
303 	/* Create a local copy of the FADT in common ACPI 2.0+ format */
304 
305 	acpi_tb_create_local_fadt(table, length);
306 
307 	/* All done with the real FADT, unmap it */
308 
309 	acpi_tb_put_table(fadt_desc);
310 
311 	/* Obtain the DSDT and FACS tables via their addresses within the FADT */
312 
313 	acpi_tb_install_standard_table((acpi_physical_address)acpi_gbl_FADT.
314 				       Xdsdt,
315 				       ACPI_TABLE_ORIGIN_INTERNAL_PHYSICAL,
316 				       NULL, FALSE, TRUE, &acpi_gbl_dsdt_index);
317 
318 	if (acpi_gbl_FADT.facs) {
319 		acpi_tb_install_standard_table((acpi_physical_address)
320 					       acpi_gbl_FADT.facs,
321 					       ACPI_TABLE_ORIGIN_INTERNAL_PHYSICAL,
322 					       NULL, FALSE, TRUE,
323 					       &acpi_gbl_facs_index);
324 	}
325 	if (acpi_gbl_FADT.Xfacs) {
326 		acpi_tb_install_standard_table((acpi_physical_address)
327 					       acpi_gbl_FADT.Xfacs,
328 					       ACPI_TABLE_ORIGIN_INTERNAL_PHYSICAL,
329 					       NULL, FALSE, TRUE,
330 					       &acpi_gbl_xfacs_index);
331 	}
332 }
333 
334 /*******************************************************************************
335  *
336  * FUNCTION:    acpi_tb_create_local_fadt
337  *
338  * PARAMETERS:  table               - Pointer to BIOS FADT
339  *              length              - Length of the table
340  *
341  * RETURN:      None
342  *
343  * DESCRIPTION: Get a local copy of the FADT and convert it to a common format.
344  *              Performs validation on some important FADT fields.
345  *
346  * NOTE:        We create a local copy of the FADT regardless of the version.
347  *
348  ******************************************************************************/
349 
350 void acpi_tb_create_local_fadt(struct acpi_table_header *table, u32 length)
351 {
352 	/*
353 	 * Check if the FADT is larger than the largest table that we expect
354 	 * (typically the current ACPI specification version). If so, truncate
355 	 * the table, and issue a warning.
356 	 */
357 	if (length > sizeof(struct acpi_table_fadt)) {
358 		ACPI_BIOS_WARNING((AE_INFO,
359 				   "FADT (revision %u) is longer than %s length, "
360 				   "truncating length %u to %u",
361 				   table->revision, ACPI_FADT_CONFORMANCE,
362 				   length,
363 				   (u32)sizeof(struct acpi_table_fadt)));
364 	}
365 
366 	/* Clear the entire local FADT */
367 
368 	memset(&acpi_gbl_FADT, 0, sizeof(struct acpi_table_fadt));
369 
370 	/* Copy the original FADT, up to sizeof (struct acpi_table_fadt) */
371 
372 	memcpy(&acpi_gbl_FADT, table,
373 	       ACPI_MIN(length, sizeof(struct acpi_table_fadt)));
374 
375 	/* Take a copy of the Hardware Reduced flag */
376 
377 	acpi_gbl_reduced_hardware = FALSE;
378 	if (acpi_gbl_FADT.flags & ACPI_FADT_HW_REDUCED) {
379 		acpi_gbl_reduced_hardware = TRUE;
380 	}
381 
382 	/* Convert the local copy of the FADT to the common internal format */
383 
384 	acpi_tb_convert_fadt();
385 
386 	/* Initialize the global ACPI register structures */
387 
388 	acpi_tb_setup_fadt_registers();
389 }
390 
391 /*******************************************************************************
392  *
393  * FUNCTION:    acpi_tb_convert_fadt
394  *
395  * PARAMETERS:  none - acpi_gbl_FADT is used.
396  *
397  * RETURN:      None
398  *
399  * DESCRIPTION: Converts all versions of the FADT to a common internal format.
400  *              Expand 32-bit addresses to 64-bit as necessary. Also validate
401  *              important fields within the FADT.
402  *
403  * NOTE:        acpi_gbl_FADT must be of size (struct acpi_table_fadt), and must
404  *              contain a copy of the actual BIOS-provided FADT.
405  *
406  * Notes on 64-bit register addresses:
407  *
408  * After this FADT conversion, later ACPICA code will only use the 64-bit "X"
409  * fields of the FADT for all ACPI register addresses.
410  *
411  * The 64-bit X fields are optional extensions to the original 32-bit FADT
412  * V1.0 fields. Even if they are present in the FADT, they are optional and
413  * are unused if the BIOS sets them to zero. Therefore, we must copy/expand
414  * 32-bit V1.0 fields to the 64-bit X fields if the 64-bit X field is originally
415  * zero.
416  *
417  * For ACPI 1.0 FADTs (that contain no 64-bit addresses), all 32-bit address
418  * fields are expanded to the corresponding 64-bit X fields in the internal
419  * common FADT.
420  *
421  * For ACPI 2.0+ FADTs, all valid (non-zero) 32-bit address fields are expanded
422  * to the corresponding 64-bit X fields, if the 64-bit field is originally
423  * zero. Adhering to the ACPI specification, we completely ignore the 32-bit
424  * field if the 64-bit field is valid, regardless of whether the host OS is
425  * 32-bit or 64-bit.
426  *
427  * Possible additional checks:
428  *  (acpi_gbl_FADT.pm1_event_length >= 4)
429  *  (acpi_gbl_FADT.pm1_control_length >= 2)
430  *  (acpi_gbl_FADT.pm_timer_length >= 4)
431  *  Gpe block lengths must be multiple of 2
432  *
433  ******************************************************************************/
434 
435 static void acpi_tb_convert_fadt(void)
436 {
437 	const char *name;
438 	struct acpi_generic_address *address64;
439 	u32 address32;
440 	u8 length;
441 	u8 flags;
442 	u32 i;
443 
444 	/*
445 	 * For ACPI 1.0 FADTs (revision 1 or 2), ensure that reserved fields which
446 	 * should be zero are indeed zero. This will workaround BIOSs that
447 	 * inadvertently place values in these fields.
448 	 *
449 	 * The ACPI 1.0 reserved fields that will be zeroed are the bytes located
450 	 * at offset 45, 55, 95, and the word located at offset 109, 110.
451 	 *
452 	 * Note: The FADT revision value is unreliable. Only the length can be
453 	 * trusted.
454 	 */
455 	if (acpi_gbl_FADT.header.length <= ACPI_FADT_V2_SIZE) {
456 		acpi_gbl_FADT.preferred_profile = 0;
457 		acpi_gbl_FADT.pstate_control = 0;
458 		acpi_gbl_FADT.cst_control = 0;
459 		acpi_gbl_FADT.boot_flags = 0;
460 	}
461 
462 	/*
463 	 * Now we can update the local FADT length to the length of the
464 	 * current FADT version as defined by the ACPI specification.
465 	 * Thus, we will have a common FADT internally.
466 	 */
467 	acpi_gbl_FADT.header.length = sizeof(struct acpi_table_fadt);
468 
469 	/*
470 	 * Expand the 32-bit DSDT addresses to 64-bit as necessary.
471 	 * Later ACPICA code will always use the X 64-bit field.
472 	 */
473 	acpi_gbl_FADT.Xdsdt = acpi_tb_select_address("DSDT",
474 						     acpi_gbl_FADT.dsdt,
475 						     acpi_gbl_FADT.Xdsdt);
476 
477 	/* If Hardware Reduced flag is set, we are all done */
478 
479 	if (acpi_gbl_reduced_hardware) {
480 		return;
481 	}
482 
483 	/* Examine all of the 64-bit extended address fields (X fields) */
484 
485 	for (i = 0; i < ACPI_FADT_INFO_ENTRIES; i++) {
486 		/*
487 		 * Get the 32-bit and 64-bit addresses, as well as the register
488 		 * length and register name.
489 		 */
490 		address32 = *ACPI_ADD_PTR(u32,
491 					  &acpi_gbl_FADT,
492 					  fadt_info_table[i].address32);
493 
494 		address64 = ACPI_ADD_PTR(struct acpi_generic_address,
495 					 &acpi_gbl_FADT,
496 					 fadt_info_table[i].address64);
497 
498 		length = *ACPI_ADD_PTR(u8,
499 				       &acpi_gbl_FADT,
500 				       fadt_info_table[i].length);
501 
502 		name = fadt_info_table[i].name;
503 		flags = fadt_info_table[i].flags;
504 
505 		/*
506 		 * Expand the ACPI 1.0 32-bit addresses to the ACPI 2.0 64-bit "X"
507 		 * generic address structures as necessary. Later code will always use
508 		 * the 64-bit address structures.
509 		 *
510 		 * November 2013:
511 		 * Now always use the 64-bit address if it is valid (non-zero), in
512 		 * accordance with the ACPI specification which states that a 64-bit
513 		 * address supersedes the 32-bit version. This behavior can be
514 		 * overridden by the acpi_gbl_use32_bit_fadt_addresses flag.
515 		 *
516 		 * During 64-bit address construction and verification,
517 		 * these cases are handled:
518 		 *
519 		 * Address32 zero, Address64 [don't care]   - Use Address64
520 		 *
521 		 * No override: if acpi_gbl_use32_bit_fadt_addresses is FALSE, and:
522 		 * Address32 non-zero, Address64 zero       - Copy/use Address32
523 		 * Address32 non-zero == Address64 non-zero - Use Address64
524 		 * Address32 non-zero != Address64 non-zero - Warning, use Address64
525 		 *
526 		 * Override: if acpi_gbl_use32_bit_fadt_addresses is TRUE, and:
527 		 * Address32 non-zero, Address64 zero       - Copy/use Address32
528 		 * Address32 non-zero == Address64 non-zero - Copy/use Address32
529 		 * Address32 non-zero != Address64 non-zero - Warning, copy/use Address32
530 		 *
531 		 * Note: space_id is always I/O for 32-bit legacy address fields
532 		 */
533 		if (address32) {
534 			if (address64->address) {
535 				if (address64->address != (u64)address32) {
536 
537 					/* Address mismatch */
538 
539 					ACPI_BIOS_WARNING((AE_INFO,
540 							   "32/64X address mismatch in FADT/%s: "
541 							   "0x%8.8X/0x%8.8X%8.8X, using %u-bit address",
542 							   name, address32,
543 							   ACPI_FORMAT_UINT64
544 							   (address64->address),
545 							   acpi_gbl_use32_bit_fadt_addresses
546 							   ? 32 : 64));
547 				}
548 
549 				/*
550 				 * For each extended field, check for length mismatch
551 				 * between the legacy length field and the corresponding
552 				 * 64-bit X length field.
553 				 * Note: If the legacy length field is > 0xFF bits, ignore
554 				 * this check. (GPE registers can be larger than the
555 				 * 64-bit GAS structure can accommodate, 0xFF bits).
556 				 */
557 				if ((ACPI_MUL_8(length) <= ACPI_UINT8_MAX) &&
558 				    (address64->bit_width !=
559 				     ACPI_MUL_8(length))) {
560 					ACPI_BIOS_WARNING((AE_INFO,
561 							   "32/64X length mismatch in FADT/%s: %u/%u",
562 							   name,
563 							   ACPI_MUL_8(length),
564 							   address64->
565 							   bit_width));
566 				}
567 			}
568 
569 			/*
570 			 * Hardware register access code always uses the 64-bit fields.
571 			 * So if the 64-bit field is zero or is to be overridden,
572 			 * initialize it with the 32-bit fields.
573 			 * Note that when the 32-bit address favor is specified, the
574 			 * 64-bit fields are always re-initialized so that
575 			 * access_size/bit_width/bit_offset fields can be correctly
576 			 * configured to the values to trigger a 32-bit compatible
577 			 * access mode in the hardware register access code.
578 			 */
579 			if (!address64->address
580 			    || acpi_gbl_use32_bit_fadt_addresses) {
581 				acpi_tb_init_generic_address(address64,
582 							     ACPI_ADR_SPACE_SYSTEM_IO,
583 							     length,
584 							     (u64)address32,
585 							     name, flags);
586 			}
587 		}
588 
589 		if (fadt_info_table[i].flags & ACPI_FADT_REQUIRED) {
590 			/*
591 			 * Field is required (Pm1a_event, Pm1a_control).
592 			 * Both the address and length must be non-zero.
593 			 */
594 			if (!address64->address || !length) {
595 				ACPI_BIOS_ERROR((AE_INFO,
596 						 "Required FADT field %s has zero address and/or length: "
597 						 "0x%8.8X%8.8X/0x%X",
598 						 name,
599 						 ACPI_FORMAT_UINT64(address64->
600 								    address),
601 						 length));
602 			}
603 		} else if (fadt_info_table[i].flags & ACPI_FADT_SEPARATE_LENGTH) {
604 			/*
605 			 * Field is optional (Pm2_control, GPE0, GPE1) AND has its own
606 			 * length field. If present, both the address and length must
607 			 * be valid.
608 			 */
609 			if ((address64->address && !length) ||
610 			    (!address64->address && length)) {
611 				ACPI_BIOS_WARNING((AE_INFO,
612 						   "Optional FADT field %s has valid %s but zero %s: "
613 						   "0x%8.8X%8.8X/0x%X", name,
614 						   (length ? "Length" :
615 						    "Address"),
616 						   (length ? "Address" :
617 						    "Length"),
618 						   ACPI_FORMAT_UINT64
619 						   (address64->address),
620 						   length));
621 			}
622 		}
623 	}
624 }
625 
626 /*******************************************************************************
627  *
628  * FUNCTION:    acpi_tb_setup_fadt_registers
629  *
630  * PARAMETERS:  None, uses acpi_gbl_FADT.
631  *
632  * RETURN:      None
633  *
634  * DESCRIPTION: Initialize global ACPI PM1 register definitions. Optionally,
635  *              force FADT register definitions to their default lengths.
636  *
637  ******************************************************************************/
638 
639 static void acpi_tb_setup_fadt_registers(void)
640 {
641 	struct acpi_generic_address *target64;
642 	struct acpi_generic_address *source64;
643 	u8 pm1_register_byte_width;
644 	u32 i;
645 
646 	/*
647 	 * Optionally check all register lengths against the default values and
648 	 * update them if they are incorrect.
649 	 */
650 	if (acpi_gbl_use_default_register_widths) {
651 		for (i = 0; i < ACPI_FADT_INFO_ENTRIES; i++) {
652 			target64 =
653 			    ACPI_ADD_PTR(struct acpi_generic_address,
654 					 &acpi_gbl_FADT,
655 					 fadt_info_table[i].address64);
656 
657 			/*
658 			 * If a valid register (Address != 0) and the (default_length > 0)
659 			 * (Not a GPE register), then check the width against the default.
660 			 */
661 			if ((target64->address) &&
662 			    (fadt_info_table[i].default_length > 0) &&
663 			    (fadt_info_table[i].default_length !=
664 			     target64->bit_width)) {
665 				ACPI_BIOS_WARNING((AE_INFO,
666 						   "Invalid length for FADT/%s: %u, using default %u",
667 						   fadt_info_table[i].name,
668 						   target64->bit_width,
669 						   fadt_info_table[i].
670 						   default_length));
671 
672 				/* Incorrect size, set width to the default */
673 
674 				target64->bit_width =
675 				    fadt_info_table[i].default_length;
676 			}
677 		}
678 	}
679 
680 	/*
681 	 * Get the length of the individual PM1 registers (enable and status).
682 	 * Each register is defined to be (event block length / 2). Extra divide
683 	 * by 8 converts bits to bytes.
684 	 */
685 	pm1_register_byte_width = (u8)
686 	    ACPI_DIV_16(acpi_gbl_FADT.xpm1a_event_block.bit_width);
687 
688 	/*
689 	 * Calculate separate GAS structs for the PM1x (A/B) Status and Enable
690 	 * registers. These addresses do not appear (directly) in the FADT, so it
691 	 * is useful to pre-calculate them from the PM1 Event Block definitions.
692 	 *
693 	 * The PM event blocks are split into two register blocks, first is the
694 	 * PM Status Register block, followed immediately by the PM Enable
695 	 * Register block. Each is of length (pm1_event_length/2)
696 	 *
697 	 * Note: The PM1A event block is required by the ACPI specification.
698 	 * However, the PM1B event block is optional and is rarely, if ever,
699 	 * used.
700 	 */
701 
702 	for (i = 0; i < ACPI_FADT_PM_INFO_ENTRIES; i++) {
703 		source64 =
704 		    ACPI_ADD_PTR(struct acpi_generic_address, &acpi_gbl_FADT,
705 				 fadt_pm_info_table[i].source);
706 
707 		if (source64->address) {
708 			acpi_tb_init_generic_address(fadt_pm_info_table[i].
709 						     target, source64->space_id,
710 						     pm1_register_byte_width,
711 						     source64->address +
712 						     (fadt_pm_info_table[i].
713 						      register_num *
714 						      pm1_register_byte_width),
715 						     "PmRegisters", 0);
716 		}
717 	}
718 }
719